Phillips will give the Orioles a third left-handed reliever for the September playoff push, joining Brian Matusz and Randy Wolf, both of whom have spent most of their careers as starters. Troy Patton, the Orioles' sole mainstay left-handed reliever for most of the season, is slowly working his way back from a sprained right ankle.

"Zach pitched real well here last year," Orioles manager Buck Showalter said. "He's been throwing the ball well down there."

Phillips' arrival comes at the perfect time, after Matusz had pitched in three consecutive games and Wolf threw 3 1/3 innings in relief in the Orioles' 8-3 win over the Yankees on Sunday.

Phillips was one of the team's final cuts this spring — he allowed just two earned runs and four hits over 11 innings for a 1.35 ERA during spring training — and flourished during a late-season call up last season, when he held left-handed hitters to a .100 batting average (2-for-20). In 10 relief appearances with the Orioles, he pitched to a 1.13 ERA and held hitters to a .194 average.

Phillips has actually been better against right-handed hitters this season, holding them to a .237 mark vs. a .325 season-mark against lefties. But Showalter said Phillips' numbers against lefties have improved considerably in the second half.

"I think I'm throwing everything for strikes right now," Phillips said. "Getting ahead of hitters has really helped me. I'm just trying to bring that here and keep it going."

Phillips was 2-2 with a 3.17 ERA and seven saves in 54 innings (42 appearances) at Norfolk. He's thrown five straight scoreless outings, allowing just one hit in a span of 4 1/3 innings. Eight of his past 10 appearances have been scoreless.

Berken was 5-6 with a 3.50 ERA in 26 starts for the Tides. He made one relief appearance for the Orioles this season, allowing seven runs (two earned) in one inning. Over four seasons with the Orioles, Berken was 10-17 with a 5.40 ERA, including a 2010 season in which he was 3-3 with a 3.03 ERA in 41 relief appearances.

The Orioles couldn't get an MRI to get a more distinct look at what was causing right-hander Chris Tillman's dead throwing elbow on Monday because of Labor Day. But the team planned to get the test done early Tuesday and have more information on the injury by that afternoon.

Tillman said he saw the MRI as a precaution, but Showalter wasn't necessarily that optimistic.

"When we get the report back, I'll tell you whether it was precautionary or not," Showalter said. "He wanted to continue. He said he wasn't feeling any acute pain, but I just didn't like the way he was describing it. He's still 20 or 30 innings away from his high in 2010. We'll see. That's why [you make] some of the acquisitions you do. You never know what each day is going to bring. You've got to keep everybody active."

Between the majors and Triple-A Norfolk, Tillman has pitched 153 1/3 innings, 22 innings less than his previous highest season total. He threw 185 innings in 2010 with the Orioles and Norfolk.

Right-hander Jake Arrieta, the Opening Day starter who battled inconsistency at the major league level this season, has likely earned himself a September call up with a strong finish at Triple-A Norfolk.

Starting the Tides' season finale Monday, Arrieta allowed just one earned run on three hits over five innings, striking out nine and walking one.

Arrieta has allowed three or fewer hits in each of his past four starts, pitching to a 1.82 ERA with 31 strikeouts and nine walks over 24 2/3 innings.

Showalter said Arrieta was limited to five-to-six innings or 80 pitches, whichever came first.

Arrieta would likely come out of the bullpen at first.

"We're trying to shorten him up a little bit in case there's a need," Showalter said.

Around the horn

The Orioles will decide whether right-hander Jason Hammel will be activated off the DL (right knee surgery) following his bullpen session Tuesday. Hammel said he's ready. If he is activated, he would likely start Thursday's home game against the Yankees. … Right fielder Nick Markakis was hit by a pitch on the left bicep in his first at-bat Sunday, but stayed in the game and hit an RBI double. Markakis has hit safely in 15 of his past 17 games and has recorded seven RBIs in his past seven contests. … The Orioles are 22-14 in games started by a left-handed pitcher. They are 25-13 in day games (including a 15-6 mark on the road). … Right-hander Tommy Hunter was recalled from Double-A Bowie before Monday's game and will work out of the bullpen. … Left-hander Zach Britton, slated to start Tuesday, joined the team Monday in Toronto, but won't be formally recalled before Tuesday's game. … Second baseman Brian Roberts has completed his 30-day rehab for hip surgery in Vail, Colo., and has reported back to Sarasota.

For a starting pitcher coming off a poor outing, the four days leading up to his next start are the most brutal. There’s plenty of time to think, to replay the mistakes over in your mind, to overanalyze.